Conventionally, inkjet printers have ejected ink from nozzles in communication with respective pressure chambers using piezoelectric elements to vibrate diaphragms covering the pressure chambers in order to change the pressure in the pressure chambers. One such inkjet printer known in the art also adjusts the initial deflection positions of these diaphragms.
The liquid jet unit of this conventional inkjet printer is provided with piezoelectric elements for applying pressure to the pressure chambers through the diaphragms, and a sealed space accommodating the piezoelectric elements. The pressure in the sealed space is adjusted so that the deflection of the diaphragm when voltage is applied to the corresponding piezoelectric element is symmetrical about a reference plane to the deflection of the diaphragm when voltage is not applied to the piezoelectric element.